Report Warns About EV’s Environmental Impact

Operating electric vehicles offers as much as a 24% reduction in global warming potential (GWP) compared to piston-powered vehicles, according to research by the Norwegian University of Science and Technology.

But the study also says manufacturing EVs has twice the GWP as making conventionally powered cars. Results are published online the current Journal of Industrial Ecology.

The analysis says the operational advantages of EVs can be sharply reduced and sometimes eliminated entirely by the impact of production and assumptions about vehicle life, battery replacement schedules and methods of generating electricity.

For example, the advantage in GWP of electrics over gasoline IC vehicles plunges by as much as two-thirds if the assumed service life of an EV is 100,000 km (62,000 miles) instead of 200,000 km (124,000 miles), according to the study.

It says the lower GWP for electrics compared with diesels drops from about 20% to zero under the same assumptions.

The study assesses the impact of EVs and piston-powered vehicles across 10 categories. It concludes that EVs appear to carry a higher risk than do piston-powered vehicles for toxicity, fresh water eutrophication and metal depletion.

The researchers point out that EVs could be used to make "drastic reductions" in the environmental impact of transportation but only if charging them can be accomplished with "clean" power. It says it would be "counterproductive" to promote EVs in regions where electricity is primarily produced by coal, lignite or heavy oil.

In those areas, the researchers say, switching to EVs would move emissions away from the roadway but not reduce them overall.